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Cobalt-, iron-, and copper-substituted nickel-aluminum hydrotalcite-like compounds (Ni2.7Co0.3Al, Ni2.7Fe0.3Al, Ni2.7Cu0.3Al HTlcs) have been synthesized and used as precursors to prepare Ni–Co, Ni–Fe, and Ni–Cu alloy catalysts for methane decomposition. The catalysts before and after reaction were characterized with various techniques including XRD, H2-TPR, HAADF-STEM-EDX, SEM, TEM, and Raman. The characterization results indicate that upon calcination HTlcs are transformed into a mixed oxide solid solution, where cobalt, copper, and iron ions are incorporated into the nickel oxide, and the reduction treatment leads to composition-uniform alloy particles. In methane decomposition at 600 °C, alloying Ni with Co, Fe, and especially Cu is found to enhance the catalytic life and carbon yield. The order of activity is Ni2.7Cu0.3Al >> Ni2.7Fe0.3Al > Ni2.7Co0.3Al > Ni3Al in terms of carbon yield, highlighting that Ni–Cu alloying is the most effective. Besides, Ni–Cu alloying remarkably changes the carbon morphology, giving carbon nanofibers as the main product. TEM and STEM measurements suggest that Ni–Cu alloy particles are readily aggregated into big particles (>60 nm) under the reaction conditions, which may be responsible for the significant effect of Ni–Cu alloying.

Various Ni–Fe/Mg(Al)O alloy catalysts were obtained by calcination of Ni–Fe–Mg–Al hydrotalcite-like compounds, followed by reduction at different temperatures (973–1173 K). The characterizations of XRD and STEM-EDX suggest that the resulting Ni–Fe alloy particles are composition-uniform and size-controllable. The alloy composition is little affected by the reduction temperature, whereas the particle size (5.8–8.2 nm) increases with the increase of reduction temperature. This property is ascribed to the homogeneous distribution of nickel and iron species during the catalyst preparation. All of the Ni–Fe/Mg(Al)O alloy catalysts show relatively high and stable activity for CH4–CO2 reforming during 25 h of investigation at 773–1073 K. Particularly, the 973 K-reduced catalyst exhibits higher coke-resistance due to its smaller particle size. Ea-CH4 and CH4-TPSR measurements indicate that Ni–Fe alloying inhibits CH4 dissociation. It is considered that during DRM CH4 is dissociated at the Ni sites and CO2 may be activated at the metal-support interface as well as the Fe sites. Ni–Fe alloying may inhibit CH4 dissociation and/or promote CO2 activation, thus contributing to the suppression of coke deposition.

A series of Ni catalysts were prepared from Ni–Al hydrotalcite-like compounds (HTlcs) by varying the Ni/Al molar ratio (1–4) and calcination temperature (773–1173 K) of HTlcs. The catalysts were reduced with H2 at 1073 K and tested for CH4 decomposition at 773–923 K on a thermal gravimeter. Various techniques including N2 physical adsorption, XRD, H2-TPR, XPS, HAADF-STEM, TEM, and Raman were applied to characterize the catalysts and the as-produced carbon. The characterizations show that calcination of Ni–Al HTlcs leads to Ni(Al)O solid solution and minor NiO and/or NiAl2O4 spinel may be formed depending on the Ni/Al ratio and calcination temperature; upon reduction at 1073 K, most nickel species are reduced to metallic Ni. In CH4 decomposition, carbon yield shows a volcano-type dependence on the Ni content with the optimum Ni/Al ratio equal to 3. On the other hand, carbon yield is affected by the calcination temperature of the Ni3Al HTlcs to a small extent. Carbon yield is also significantly affected by the reaction temperature, which decreases remarkably with a rise of temperature to 923 K. TEM and Raman indicate that fish-bone carbon nanofibers are formed at 773–823 K, whereas multi-walled carbon nanotubes are formed at 873–923 K.

Organic manure is beneficial for macro-aggregate formation and soil organic carbon (SOC), but how SOC change in aggregate fractions in time-series is still uncertain. Moreover, greenhouse systems converted from cereal fields quickly faced soil degradation. Thus, the role of organic manure here should be discussed. The main objectives of this study were to determine the change of SOC fractions in bulk soil and aggregation level affected by long-term organic manure application. Using 13C solid-state nuclear magnetic resonance (NMR) spectroscopy, we investigated the SOC and its fraction changes within bulk soil and aggregate fractions under 1-year, 9-year, and 14-year organic greenhouse vegetable cultivation, and we also analysed the soil properties of rice-wheat rotation (RWR) fields as the control. Soil aggregate samples were wet sieved into large macro-aggregates (> 2 mm), small macro-aggregates (2–0.25 mm), micro-aggregates (0.053–0.25 mm), and silt and clay particles (

Hydrotalcite-derived Ni/Mg(Al)O is promising for CH4–CO2 reforming. However, the catalysts reported so far suffer from sever coking at low temperatures. In this work, we demonstrate that a significant improvement of coke-resistance of Ni/Mg(Al)O can be achieved by fine tuning the Ni particle size through adjusting the reduction condition of catalyst. Ni particles having average size within 4.0–7.1 nm are in situ generated by reducing the catalyst at a selected temperature within 923–1073 K. Controllability of Ni particle size is related to the formation of Mg(Ni,Al)O solid solution upon hydrotalcite decomposition. It is found that the catalyst reduced at 973 K exhibits high activity, stability, and coke-resistance even at reaction temperature as low as 773 K. In contrast, the catalyst reduced at 923 K has low activity and deactivates due to Ni oxidation, while those reduced at 1023 and 1073 K suffer from sintering and severe coking. STEM and O2-TPO reveal that coke deposition is directly proportional to the Ni particle size but becomes negligible at a size below 6.2 nm. It is evidenced that a critical size of about 6 nm is required to inhibit coking effectively. CO2 temperature-programmed surface reaction indicates that the deposited carbon on small Ni particles can be easily removed by the CO2 activated at the Ni–Mg(Al)O interfaces, accounting for the better resistance to coking.

Crude fucoidan was extracted from the Saccharina sculpera from Rongcheng cultivation area in Sanggou Bay in the Yellow Sea of China which was sampled monthly from March to July. The crude fucoidan yield of S. sculpera showed an increase from 2.9% in March to 6.1% dry wt in July as the plant matured. And the content of polysaccharide (from 0.55 to 1.46% dry wt) and sulfate (from 0.37 to 1.62% dry wt) tended to increase from March to July as well. The monosaccharide composition changed constantly in the growing period with an increase of fucose (from 32.15 to 60.85 mol%) and a decrease of galactose (from 21.89 to 9.03 mol%). Analysis results showed that the content of crude fucoidan, polysaccharide, and sulfate in matured season was higher than that of other three species of farmed brown algae Saccharina japonica, Costaria costata, and Undaria pinnatifida in the same waters. These data indicated that S. sculpera was an excellent algal species in fucoidan content. This study on seasonal variations of polysaccharide, sulfate content, and monosaccharide composition provides a practical guidance for determining the optimal opportunity for harvesting the algae in order to standardize preparations of fucoidan for use in the pharmaceutical industry.

The seasonal growth, seedling raising and artificial cultivation of Sargassum confusum were studied along the coast of Dong Chudao at the mouth of Sanggou Bay (37°02′12″N, 122°33′51″E). We also compared the growth of juveniles at different temperatures (15, 18, 21, and 24 °C) and irradiances (60, 95, and 130 μmol photons m−2 s−1) when seedlings were raised in a greenhouse. Sargassum confusum in Sanggou Bay began to develop receptacles in early April when the seawater temperature reached 10.8 °C. The receptacles matured in July and released the eggs when the seawater temperature reached 21 °C. The S. confusum thallus grew to maximum mean length (126.6 ± 19.8 cm) and reached the highest mean biomass yield (192.2 ± 40 g dwt thallus−1) in July and then rapidly decayed. Both temperature and irradiance significantly affected the growth of S. confusum seedlings (p

The coronavirus (COVID-19) epidemic reported for the first time in Wuhan, China at the end of 2019, which has caused 4648 deaths in China as of July 10, 2020. This study explored the temporal correlation between the case fatality rate (CFR) of COVID-19 and particulate matter (PM) in Wuhan. We conducted a time series analysis to examine the temporal day-by-day associations. We observed a higher CFR of COVID-19 with increasing concentrations of inhalable particulate matter (PM) with an aerodynamic diameter of 10 μm or less (PM10) and fine PM with an aerodynamic diameter of 2.5 μm or less (PM2.5) in the temporal scale. This association may affect patients with mild to severe disease progression and affect their prognosis., Highlights • The daily PM2.5 and PM10 concentrations and the daily CFR exhibited great similarity with respect to their temporal variation curves, besides, with an obvious time lag existing between them. • The association still exists after adjusted for all possible confounders (e.g., temperature and relative humidity, SO2, NO2, CO, and O3).

This study aims to explore the relationship between ambient NO2 levels and the transmission ability (basic reproductive number, R0) of COVID-19 in 63 Chinese cities. After adjustment for temperature and relative humidity, R0 was positively associated with NO2 concentration at city level. The temporal analysis within Hubei province indicated that all the 11 Hubei cities (except Xianning City) had significant positive correlations between NO2 concentration (with 12-day time lag) and R0 (r>0.51, p, Highlights ● The basic reproductive number (R0) of COVID-19 was positively associated with NO2 in all cities after adjustment for temperature and relative humidity. ● Higher ambient NO2 level will aggravate the severity of the COVID-19 epidemic. ● Reduced population movement (NO2 decreases) may reduce the spread of the COVID-19.

Purpose To examine the association between meteorological factors (temperature, relative humidity, wind speed, and UV radiation) and transmission capacity of COVID-19. Methods We collected daily numbers of COVID-19 cases in 202 locations in 8 countries. We matched meteorological data from the NOAA National Centers for Environmental Information. We used a time-frequency approach to examine the possible association between meteorological conditions and basic reproductive number (R0) of COVID-19. We determined the correlations between meteorological factors and R0 of COVID-19 using multiple linear regression models and meta-analysis. We further validated our results using a susceptible-exposed-infectious-recovered (SEIR) metapopulation model to simulate the changes of daily cases of COVID-19 in China under different temperatures and relative humidity conditions. Principal results Temperature did not exhibit significant association with R0 of COVID-19 (meta p = 0.446). Also, relative humidity (meta p = 0.215), wind speed (meta p = 0.986), and ultraviolet (UV) radiation (meta p = 0.491) were not significantly associated with R0 either. The SEIR model in China showed that with a wide range of meteorological conditions, the number of COVID-19 confirmed cases would not change substantially. Conclusions Meteorological conditions did not have statistically significant associations with the R0 of COVID-19. Warmer weather alone seems unlikely to reduce the COVID-19 transmission., Graphical abstract Unlabelled Image, Highlights • Temperature did not exhibit significant associations with COVID-19's R0. • Other meteorological factors weren't significantly associated with COVID-19's R0. • It's unlikely to depend on warmer weather to reduce the COVID-19 transmission.

The COVID-19 epidemic, caused by the SARS-CoV-2 virus, has resulted in 3352 deaths in China as of April 12, 2020. This study aimed to investigate the associations between particulate matter (PM) concentrations and the case fatality rate (CFR) of COVID-19 in 49 Chinese cities, including the epicenter of Wuhan. We used the Global Moran's I to analyze spatial distribution and autocorrelation of CFRs, and then we used multivariate linear regression to analyze the associations between PM2.5 and PM10 concentrations and COVID-19 CFR. We found positive associations between PM pollution and COVID-19 CFR in cities both inside and outside Hubei Province. For every 10 μg/m3 increase in PM2.5 and PM10 concentrations, the COVID-19 CFR increased by 0.24% (0.01%–0.48%) and 0.26% (0.00%–0.51%), respectively. PM pollution distribution and its association with COVID-19 CFR suggests that exposure to such may affect COVID-19 prognosis., Graphical abstract Unlabelled Image, Highlights • Spatial analysis showed a high-high death rate clustering located in Hubei Province. • Particulate matter (PM) pollution was positively associated with COVID-19 CFR. • The positive associations happened in cities both inside and outside Hubei Province. • Results suggested that exposure to PM may affect COVID-19 prognosis.

Dongfang no. 6, an intraspecific hybrid of kelp (Saccharina japonica) which was high in yield and had a high stress tolerance and was suitable for processing, was bred by crossing scientifically selected parental gametophyte clones. The sporophyte of the hybrid was raised by crossing a female gametophyte clone isolated from a Korean ecotype of S. japonica (Korean kelp) with a male gametophyte clone isolated from Lianza no. 1, a variety of S. japonica bred through continuous selection. The culture performance, stress tolerance, and suitability for processing of the hybrid and two commercial controls were compared for a period lasting 5 years (2009–2013). It was found that the hybrid was fast in growth, tolerant to high seawater temperature, resistant to strong solar irradiation, late in maturing time, and high in processed product yield. The percentage of salting processed product of the hybrid was 17.5 and 15.4 % higher than those of control 1 and 2, respectively. The yield of salting processed product of the hybrid increased by 24.2 and 38.8 % over control 1 and 2, respectively. The yield of air drying processed product of the hybrid increased by 109.4 and 88.1 % over control 1 and 2, respectively. The breeding of Dongfang no. 6 demonstrated that crossing gametophyte clones in combination with selecting desirable hybrids are highly effective for breeding kelp hybrids with high-culture performance and suitability for processing.

Dongfang no.7 (Saccharina japonica) was bred and maintained by hybridizing gametophytes, self-crossing the best individuals, selecting the best self-crossing line and seedling-raising from yearly reconstructed sporophytes. It increased the air dry yield by 43.2% in average over 2 widely farmed controls. Dongfang no.7 was seedling-raised from bulked sporophytes reconstructed from its representative gametophyte clones. Such strategy ensured it against variety contamination due to possible cross fertilization and occasional mixing and inbred depletion due to self-crossing number-limited sporophytes year after year. It derived from an intraspecific hybrid through 4 rounds of self-crossing and selection and retained a certain degree of genetic heterozygosity, thus being immune to inbred depletion due to purification of unknown detrimental alleles. Most importantly, it can be farmed in currently available system as the seedlings for large scale culture can be raised from reconstructed Dongfang no.7 sporophytes. Breeding and maintaining Dongfang no.7 provided a model that other varieties of kelp (S. japonica) and brown algae may follow during their domestication.